Biological assay systems are becoming increasingly more important in bio-technology and medical diagnostics. A useful biological agent detection method is using DNA or RNA detection of an organism through a polymerase chain reaction (PCR), real-time polymerase chain reaction (RT-PCR), or reverse-transcriptase polymerase chain reaction. Alternatively, assaying for the presence of a particular cellular protein can also be used to detect or study biological samples of interest. Before a cell or environment sample can be analyzed using PCR or protein analysis for example, it must first be prepared for analysis. A challenge in biological sample preparation is lysis of the cell membrane and, if present, the cell wall.
Common lysis techniques comprise at least three categories: chemical lysis, mechanical, lysis, and thermal lysis. Chemical lysis involves exposing the biological sample of interest to a cocktail of solvents and harsh chemicals that promote the degeneration of the cell membrane. This permits easy access to the biological sample's genetic material, intracellular proteins or cellular lipids. Although chemical lysis can be effective, each chemical cocktail needs to be tailored to the organism of interest. This requires that the chemical cocktail be completely redesigned to perform lysis on a different biological sample.
A second method of lysis is thermal lysis. Heating cells to a high temperature causes cellular protein denaturation and cell membrane breakdown. This method is not ideal when the goal is to assay for relatively rare DNA, RNA or protein targets, as the harsh process of thermal lysis may destroy the target to be detected.
A third approach to cell lysis is mechanical lysis. This method uses a crushing or grinding action to cleave cell membranes. For example, glass beads can be centrifuged along with the sample at a high angular velocity, cleaving cells as they grind past each other. Some centrifuge systems also rock the sample using three dimensional movements to increase the efficiency of lysis. Another method of mechanical lysis is to pressure the cell sample and flow it past a piercing object at a high velocity. This however requires a significant amount of external equipment such as expensive and bulky vacuum pumps. There is a need, therefore, for a more compact mechanical cell lysis solution.